Automobile GPS navigation systems make available to their drivers active street and highway maps, directions, as well as complete reliable directories of restaurants, hospital descriptions, car services, and many other points of interest (POI). You will hear voice prompts and alerts which allows the driver to be attentive to the road, thus it is also a safety factor.
GPS, or the Global Positioning System was developed and created by the United States Department of Defense. It was wholly managed via the United States Air Force, using their 50th Space Wing. GPS navigation systems use a receiver in a car to calculate its position by actually timing the signals that are being sent by the GPS satellites that are located high above the earth. There were four such satellites that were used by most of the early GPA receivers depending on a myriad of complicated conditions mostly related to the speed of light.
As satellites were launched, the amount of satellites used for automobile GPS systems began to be defined by the amount of satellites it could monitor at once, and now we hear of receivers that can monitor a multitude of channels or satellites.
Occasionally the early automotive GPS receivers lost some of their reception due to the metallic features found in windshields, such as window tinting films and windshield defrosters. Occasionally too, different issues and factors that might affect its accuracy included such things as heavy foliage, tunnels, buildings, and atmospheric conditions, though the latest automotive GPS receivers have dealt well with such issues.
Aftermarket Automobile GPS are undeniably less expensive and thus are being used more often than those installed in some cars. In fact, there are many GPS experts that maintain that aftermarket GPS units are cheaper and better than those that have come factory-installed in many new cars. Part of that reasoning is the fact that factory-installed units cannot be updated and unfortunately can only be used in the single car that they are installed into. On the other hand, factory-installed GPS units present a clean, integrated installation, and also they are greatly more complicated to steal than the aftermarket automobile GPS units.
When comparing the newer advanced GPS systems you should look for those that have full-color 3-D street maps, present you traffic alerts as well as rerouting, and give you an integrated hands-free cell-phone use. The screen should be an easy touch-screen control. Paying more for a GPS will bring you wide-screens, and FM transmitters enabling you to hear the voice prompts and any alerts through the car stereo system, Bluetooth wireless connection for your cell phone, and very sophisticated theft prevention features.
New-car already built-in GPS systems offered as standard equipment or worse yet as an option on new vehicles tend to be much more expensive than add-on units. One of the advantages though is that the screen is usually bigger. Often too the LCD display is sometimes collectively shared with the other systems in the car. Thus you can read out information quickly on the hands-free cell phone, radio, as well as the climate control features. Finally with the built-in units, the power attachment and the antenna will already be part of the vehicle. Finally though, experts also agree that the built-in systems are frequently a step behind concerning any new features and also map updates.